[3][4] He was utilised as cover for injuries and had a run in the team as a stand-in right back for the injured Danny Boxall during the 1999–00 season and in central defence for Scott Marshall during 2000–01.
[8] On 7 February 2003, Theobald joined hometown Third Division club Cambridge United on a contract running until the end of the 2002–03 season.
[8] Between 2003 and 2018, Theobald had a long career in non-League football, predominantly with Cambridge City, for whom he made 274 appearances and scored 39 goals across three spells.
[10] On 8 October 2015, Theobald and fellow senior player Robbie Nightingale took over as joint-managers of Isthmian League First Division North club Soham Town Rangers.
[12][13] On 5 December 2016, Theobald returned to Southern League Premier Division club Cambridge City as first team coach.